From: Madhuparna Bhowmik <[email protected]>
This patch passes the cond argument to list_for_each_entry_rcu()
to fix the following false-positive lockdep warnings:
[ 330.302784] =============================
[ 330.302789] WARNING: suspicious RCU usage
[ 330.302796] 5.6.0-rc1+ #5 Not tainted
[ 330.302801] -----------------------------
[ 330.302808] drivers/base/power/main.c:326 RCU-list traversed in non-reader section!!
[ 330.303303] =============================
[ 330.303307] WARNING: suspicious RCU usage
[ 330.303311] 5.6.0-rc1+ #5 Not tainted
[ 330.303315] -----------------------------
[ 330.303319] drivers/base/power/main.c:1698 RCU-list traversed in non-reader section!!
[ 331.934969] =============================
[ 331.934971] WARNING: suspicious RCU usage
[ 331.934973] 5.6.0-rc1+ #5 Not tainted
[ 331.934975] -----------------------------
[ 331.934977] drivers/base/power/main.c:1238 RCU-list traversed in non-reader section!!
[ 332.467772] WARNING: suspicious RCU usage
[ 332.467775] 5.6.0-rc1+ #5 Not tainted
[ 332.467775] -----------------------------
[ 332.467778] drivers/base/power/main.c:269 RCU-list traversed in non-reader section!!
Signed-off-by: Madhuparna Bhowmik <[email protected]>
---
drivers/base/power/main.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
index 0e99a760aebd..742c05f3c1e7 100644
--- a/drivers/base/power/main.c
+++ b/drivers/base/power/main.c
@@ -266,7 +266,8 @@ static void dpm_wait_for_suppliers(struct device *dev, bool async)
* callbacks freeing the link objects for the links in the list we're
* walking.
*/
- list_for_each_entry_rcu(link, &dev->links.suppliers, c_node)
+ list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
+ device_links_read_lock_held())
if (READ_ONCE(link->status) != DL_STATE_DORMANT)
dpm_wait(link->supplier, async);
@@ -323,7 +324,8 @@ static void dpm_wait_for_consumers(struct device *dev, bool async)
* continue instead of trying to continue in parallel with its
* unregistration).
*/
- list_for_each_entry_rcu(link, &dev->links.consumers, s_node)
+ list_for_each_entry_rcu(link, &dev->links.consumers, s_node,
+ device_links_read_lock_held())
if (READ_ONCE(link->status) != DL_STATE_DORMANT)
dpm_wait(link->consumer, async);
@@ -1235,7 +1237,8 @@ static void dpm_superior_set_must_resume(struct device *dev)
idx = device_links_read_lock();
- list_for_each_entry_rcu(link, &dev->links.suppliers, c_node)
+ list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
+ device_links_read_lock_held())
link->supplier->power.must_resume = true;
device_links_read_unlock(idx);
@@ -1695,7 +1698,8 @@ static void dpm_clear_superiors_direct_complete(struct device *dev)
idx = device_links_read_lock();
- list_for_each_entry_rcu(link, &dev->links.suppliers, c_node) {
+ list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
+ device_links_read_lock_held()) {
spin_lock_irq(&link->supplier->power.lock);
link->supplier->power.direct_complete = false;
spin_unlock_irq(&link->supplier->power.lock);
--
2.17.1
On Fri, Feb 28, 2020 at 6:47 PM <[email protected]> wrote:
>
> From: Madhuparna Bhowmik <[email protected]>
>
> This patch passes the cond argument to list_for_each_entry_rcu()
> to fix the following false-positive lockdep warnings:
>
> [ 330.302784] =============================
> [ 330.302789] WARNING: suspicious RCU usage
> [ 330.302796] 5.6.0-rc1+ #5 Not tainted
> [ 330.302801] -----------------------------
> [ 330.302808] drivers/base/power/main.c:326 RCU-list traversed in non-reader section!!
>
> [ 330.303303] =============================
> [ 330.303307] WARNING: suspicious RCU usage
> [ 330.303311] 5.6.0-rc1+ #5 Not tainted
> [ 330.303315] -----------------------------
> [ 330.303319] drivers/base/power/main.c:1698 RCU-list traversed in non-reader section!!
>
> [ 331.934969] =============================
> [ 331.934971] WARNING: suspicious RCU usage
> [ 331.934973] 5.6.0-rc1+ #5 Not tainted
> [ 331.934975] -----------------------------
> [ 331.934977] drivers/base/power/main.c:1238 RCU-list traversed in non-reader section!!
>
> [ 332.467772] WARNING: suspicious RCU usage
> [ 332.467775] 5.6.0-rc1+ #5 Not tainted
> [ 332.467775] -----------------------------
> [ 332.467778] drivers/base/power/main.c:269 RCU-list traversed in non-reader section!!
I don't see these warnings in the kernels run locally here.
What do you do to get them?
Joel, any comments here?
>
> Signed-off-by: Madhuparna Bhowmik <[email protected]>
> ---
> drivers/base/power/main.c | 12 ++++++++----
> 1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
> index 0e99a760aebd..742c05f3c1e7 100644
> --- a/drivers/base/power/main.c
> +++ b/drivers/base/power/main.c
> @@ -266,7 +266,8 @@ static void dpm_wait_for_suppliers(struct device *dev, bool async)
> * callbacks freeing the link objects for the links in the list we're
> * walking.
> */
> - list_for_each_entry_rcu(link, &dev->links.suppliers, c_node)
> + list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
> + device_links_read_lock_held())
> if (READ_ONCE(link->status) != DL_STATE_DORMANT)
> dpm_wait(link->supplier, async);
>
> @@ -323,7 +324,8 @@ static void dpm_wait_for_consumers(struct device *dev, bool async)
> * continue instead of trying to continue in parallel with its
> * unregistration).
> */
> - list_for_each_entry_rcu(link, &dev->links.consumers, s_node)
> + list_for_each_entry_rcu(link, &dev->links.consumers, s_node,
> + device_links_read_lock_held())
> if (READ_ONCE(link->status) != DL_STATE_DORMANT)
> dpm_wait(link->consumer, async);
>
> @@ -1235,7 +1237,8 @@ static void dpm_superior_set_must_resume(struct device *dev)
>
> idx = device_links_read_lock();
>
> - list_for_each_entry_rcu(link, &dev->links.suppliers, c_node)
> + list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
> + device_links_read_lock_held())
> link->supplier->power.must_resume = true;
>
> device_links_read_unlock(idx);
> @@ -1695,7 +1698,8 @@ static void dpm_clear_superiors_direct_complete(struct device *dev)
>
> idx = device_links_read_lock();
>
> - list_for_each_entry_rcu(link, &dev->links.suppliers, c_node) {
> + list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
> + device_links_read_lock_held()) {
> spin_lock_irq(&link->supplier->power.lock);
> link->supplier->power.direct_complete = false;
> spin_unlock_irq(&link->supplier->power.lock);
> --
> 2.17.1
>
On March 1, 2020 3:12:53 PM EST, "Rafael J. Wysocki" <[email protected]> wrote:
>On Fri, Feb 28, 2020 at 6:47 PM <[email protected]> wrote:
>>
>> From: Madhuparna Bhowmik <[email protected]>
>>
>> This patch passes the cond argument to list_for_each_entry_rcu()
>> to fix the following false-positive lockdep warnings:
>>
>> [ 330.302784] =============================
>> [ 330.302789] WARNING: suspicious RCU usage
>> [ 330.302796] 5.6.0-rc1+ #5 Not tainted
>> [ 330.302801] -----------------------------
>> [ 330.302808] drivers/base/power/main.c:326 RCU-list traversed in
>non-reader section!!
>>
>> [ 330.303303] =============================
>> [ 330.303307] WARNING: suspicious RCU usage
>> [ 330.303311] 5.6.0-rc1+ #5 Not tainted
>> [ 330.303315] -----------------------------
>> [ 330.303319] drivers/base/power/main.c:1698 RCU-list traversed in
>non-reader section!!
>>
>> [ 331.934969] =============================
>> [ 331.934971] WARNING: suspicious RCU usage
>> [ 331.934973] 5.6.0-rc1+ #5 Not tainted
>> [ 331.934975] -----------------------------
>> [ 331.934977] drivers/base/power/main.c:1238 RCU-list traversed in
>non-reader section!!
>>
>> [ 332.467772] WARNING: suspicious RCU usage
>> [ 332.467775] 5.6.0-rc1+ #5 Not tainted
>> [ 332.467775] -----------------------------
>> [ 332.467778] drivers/base/power/main.c:269 RCU-list traversed in
>non-reader section!!
>
>I don't see these warnings in the kernels run locally here.
>
>What do you do to get them?
>
>Joel, any comments here?
You have to enable lockdep in your config. Does your setup have that?
Thanks,
- Joel
>
>>
>> Signed-off-by: Madhuparna Bhowmik <[email protected]>
>> ---
>> drivers/base/power/main.c | 12 ++++++++----
>> 1 file changed, 8 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c
>> index 0e99a760aebd..742c05f3c1e7 100644
>> --- a/drivers/base/power/main.c
>> +++ b/drivers/base/power/main.c
>> @@ -266,7 +266,8 @@ static void dpm_wait_for_suppliers(struct device
>*dev, bool async)
>> * callbacks freeing the link objects for the links in the
>list we're
>> * walking.
>> */
>> - list_for_each_entry_rcu(link, &dev->links.suppliers, c_node)
>> + list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
>> + device_links_read_lock_held())
>> if (READ_ONCE(link->status) != DL_STATE_DORMANT)
>> dpm_wait(link->supplier, async);
>>
>> @@ -323,7 +324,8 @@ static void dpm_wait_for_consumers(struct device
>*dev, bool async)
>> * continue instead of trying to continue in parallel with
>its
>> * unregistration).
>> */
>> - list_for_each_entry_rcu(link, &dev->links.consumers, s_node)
>> + list_for_each_entry_rcu(link, &dev->links.consumers, s_node,
>> + device_links_read_lock_held())
>> if (READ_ONCE(link->status) != DL_STATE_DORMANT)
>> dpm_wait(link->consumer, async);
>>
>> @@ -1235,7 +1237,8 @@ static void dpm_superior_set_must_resume(struct
>device *dev)
>>
>> idx = device_links_read_lock();
>>
>> - list_for_each_entry_rcu(link, &dev->links.suppliers, c_node)
>> + list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
>> + device_links_read_lock_held())
>> link->supplier->power.must_resume = true;
>>
>> device_links_read_unlock(idx);
>> @@ -1695,7 +1698,8 @@ static void
>dpm_clear_superiors_direct_complete(struct device *dev)
>>
>> idx = device_links_read_lock();
>>
>> - list_for_each_entry_rcu(link, &dev->links.suppliers, c_node)
>{
>> + list_for_each_entry_rcu(link, &dev->links.suppliers, c_node,
>> + device_links_read_lock_held()) {
>> spin_lock_irq(&link->supplier->power.lock);
>> link->supplier->power.direct_complete = false;
>> spin_unlock_irq(&link->supplier->power.lock);
>> --
>> 2.17.1
>>
--
Sent from my Android device with K-9 Mail. Please excuse my brevity.
On Sun, Mar 1, 2020 at 9:53 PM <[email protected]> wrote:
>
>
>
> On March 1, 2020 3:12:53 PM EST, "Rafael J. Wysocki" <[email protected]> wrote:
> >On Fri, Feb 28, 2020 at 6:47 PM <[email protected]> wrote:
> >>
> >> From: Madhuparna Bhowmik <[email protected]>
> >>
> >> This patch passes the cond argument to list_for_each_entry_rcu()
> >> to fix the following false-positive lockdep warnings:
> >>
> >> [ 330.302784] =============================
> >> [ 330.302789] WARNING: suspicious RCU usage
> >> [ 330.302796] 5.6.0-rc1+ #5 Not tainted
> >> [ 330.302801] -----------------------------
> >> [ 330.302808] drivers/base/power/main.c:326 RCU-list traversed in
> >non-reader section!!
> >>
> >> [ 330.303303] =============================
> >> [ 330.303307] WARNING: suspicious RCU usage
> >> [ 330.303311] 5.6.0-rc1+ #5 Not tainted
> >> [ 330.303315] -----------------------------
> >> [ 330.303319] drivers/base/power/main.c:1698 RCU-list traversed in
> >non-reader section!!
> >>
> >> [ 331.934969] =============================
> >> [ 331.934971] WARNING: suspicious RCU usage
> >> [ 331.934973] 5.6.0-rc1+ #5 Not tainted
> >> [ 331.934975] -----------------------------
> >> [ 331.934977] drivers/base/power/main.c:1238 RCU-list traversed in
> >non-reader section!!
> >>
> >> [ 332.467772] WARNING: suspicious RCU usage
> >> [ 332.467775] 5.6.0-rc1+ #5 Not tainted
> >> [ 332.467775] -----------------------------
> >> [ 332.467778] drivers/base/power/main.c:269 RCU-list traversed in
> >non-reader section!!
> >
> >I don't see these warnings in the kernels run locally here.
> >
> >What do you do to get them?
> >
> >Joel, any comments here?
>
> You have to enable lockdep in your config. Does your setup have that?
CONFIG_LOCK_DEBUGGING_SUPPORT=y
CONFIG_PROVE_LOCKING=y
CONFIG_DEBUG_SPINLOCK=y
CONFIG_DEBUG_LOCK_ALLOC=y
CONFIG_LOCKDEP=y
Anything else?
On Sun, Mar 1, 2020 at 4:23 PM Rafael J. Wysocki <[email protected]> wrote:
>
> On Sun, Mar 1, 2020 at 9:53 PM <[email protected]> wrote:
> >
> >
> >
> > On March 1, 2020 3:12:53 PM EST, "Rafael J. Wysocki" <[email protected]> wrote:
> > >On Fri, Feb 28, 2020 at 6:47 PM <[email protected]> wrote:
> > >>
> > >> From: Madhuparna Bhowmik <[email protected]>
> > >>
> > >> This patch passes the cond argument to list_for_each_entry_rcu()
> > >> to fix the following false-positive lockdep warnings:
> > >>
> > >> [ 330.302784] =============================
> > >> [ 330.302789] WARNING: suspicious RCU usage
> > >> [ 330.302796] 5.6.0-rc1+ #5 Not tainted
> > >> [ 330.302801] -----------------------------
> > >> [ 330.302808] drivers/base/power/main.c:326 RCU-list traversed in
> > >non-reader section!!
> > >>
> > >> [ 330.303303] =============================
> > >> [ 330.303307] WARNING: suspicious RCU usage
> > >> [ 330.303311] 5.6.0-rc1+ #5 Not tainted
> > >> [ 330.303315] -----------------------------
> > >> [ 330.303319] drivers/base/power/main.c:1698 RCU-list traversed in
> > >non-reader section!!
> > >>
> > >> [ 331.934969] =============================
> > >> [ 331.934971] WARNING: suspicious RCU usage
> > >> [ 331.934973] 5.6.0-rc1+ #5 Not tainted
> > >> [ 331.934975] -----------------------------
> > >> [ 331.934977] drivers/base/power/main.c:1238 RCU-list traversed in
> > >non-reader section!!
> > >>
> > >> [ 332.467772] WARNING: suspicious RCU usage
> > >> [ 332.467775] 5.6.0-rc1+ #5 Not tainted
> > >> [ 332.467775] -----------------------------
> > >> [ 332.467778] drivers/base/power/main.c:269 RCU-list traversed in
> > >non-reader section!!
> > >
> > >I don't see these warnings in the kernels run locally here.
> > >
> > >What do you do to get them?
> > >
> > >Joel, any comments here?
> >
> > You have to enable lockdep in your config. Does your setup have that?
>
> CONFIG_LOCK_DEBUGGING_SUPPORT=y
> CONFIG_PROVE_LOCKING=y
> CONFIG_DEBUG_SPINLOCK=y
> CONFIG_DEBUG_LOCK_ALLOC=y
> CONFIG_LOCKDEP=y
This should be it. I am not sure what else Madhuparna did to trigger
it. Madhuparna, could you elaborate?
thanks,
- Joel
On Mon, Mar 2, 2020 at 1:34 PM Madhuparna Bhowmik
<[email protected]> wrote:
>
>
>
> On Mon, 2 Mar, 2020, 3:48 AM Joel Fernandes, <[email protected]> wrote:
>>
>> On Sun, Mar 1, 2020 at 4:23 PM Rafael J. Wysocki <[email protected]> wrote:
>> >
>> > On Sun, Mar 1, 2020 at 9:53 PM <[email protected]> wrote:
>> > >
>> > >
>> > >
>> > > On March 1, 2020 3:12:53 PM EST, "Rafael J. Wysocki" <[email protected]> wrote:
>> > > >On Fri, Feb 28, 2020 at 6:47 PM <[email protected]> wrote:
>> > > >>
>> > > >> From: Madhuparna Bhowmik <[email protected]>
>> > > >>
>> > > >> This patch passes the cond argument to list_for_each_entry_rcu()
>> > > >> to fix the following false-positive lockdep warnings:
>> > > >>
>> > > >> [ 330.302784] =============================
>> > > >> [ 330.302789] WARNING: suspicious RCU usage
>> > > >> [ 330.302796] 5.6.0-rc1+ #5 Not tainted
>> > > >> [ 330.302801] -----------------------------
>> > > >> [ 330.302808] drivers/base/power/main.c:326 RCU-list traversed in
>> > > >non-reader section!!
>> > > >>
>> > > >> [ 330.303303] =============================
>> > > >> [ 330.303307] WARNING: suspicious RCU usage
>> > > >> [ 330.303311] 5.6.0-rc1+ #5 Not tainted
>> > > >> [ 330.303315] -----------------------------
>> > > >> [ 330.303319] drivers/base/power/main.c:1698 RCU-list traversed in
>> > > >non-reader section!!
>> > > >>
>> > > >> [ 331.934969] =============================
>> > > >> [ 331.934971] WARNING: suspicious RCU usage
>> > > >> [ 331.934973] 5.6.0-rc1+ #5 Not tainted
>> > > >> [ 331.934975] -----------------------------
>> > > >> [ 331.934977] drivers/base/power/main.c:1238 RCU-list traversed in
>> > > >non-reader section!!
>> > > >>
>> > > >> [ 332.467772] WARNING: suspicious RCU usage
>> > > >> [ 332.467775] 5.6.0-rc1+ #5 Not tainted
>> > > >> [ 332.467775] -----------------------------
>> > > >> [ 332.467778] drivers/base/power/main.c:269 RCU-list traversed in
>> > > >non-reader section!!
>> > > >
>> > > >I don't see these warnings in the kernels run locally here.
>> > > >
>> > > >What do you do to get them?
>> > > >
>> > > >Joel, any comments here?
>> > >
>> > > You have to enable lockdep in your config. Does your setup have that?
>> >
>> > CONFIG_LOCK_DEBUGGING_SUPPORT=y
>> > CONFIG_PROVE_LOCKING=y
>> > CONFIG_DEBUG_SPINLOCK=y
>> > CONFIG_DEBUG_LOCK_ALLOC=y
>> > CONFIG_LOCKDEP=y
>>
>>
> I had CONFIG_PROVE_RCU_LIST = y and I think these warnings were triggered when I had closed my laptop (like just close without shutting down).
OK, so let's define a macro for that in this file to avoid code duplication.
And analogously in the second patch.
Thanks!
On Mon, Mar 02, 2020 at 06:02:21PM +0100, Rafael J. Wysocki wrote:
> On Mon, Mar 2, 2020 at 1:34 PM Madhuparna Bhowmik
> <[email protected]> wrote:
> >
> >
> >
> > On Mon, 2 Mar, 2020, 3:48 AM Joel Fernandes, <[email protected]> wrote:
> >>
> >> On Sun, Mar 1, 2020 at 4:23 PM Rafael J. Wysocki <[email protected]> wrote:
> >> >
> >> > On Sun, Mar 1, 2020 at 9:53 PM <[email protected]> wrote:
> >> > >
> >> > >
> >> > >
> >> > > On March 1, 2020 3:12:53 PM EST, "Rafael J. Wysocki" <[email protected]> wrote:
> >> > > >On Fri, Feb 28, 2020 at 6:47 PM <[email protected]> wrote:
> >> > > >>
> >> > > >> From: Madhuparna Bhowmik <[email protected]>
> >> > > >>
> >> > > >> This patch passes the cond argument to list_for_each_entry_rcu()
> >> > > >> to fix the following false-positive lockdep warnings:
> >> > > >>
> >> > > >> [ 330.302784] =============================
> >> > > >> [ 330.302789] WARNING: suspicious RCU usage
> >> > > >> [ 330.302796] 5.6.0-rc1+ #5 Not tainted
> >> > > >> [ 330.302801] -----------------------------
> >> > > >> [ 330.302808] drivers/base/power/main.c:326 RCU-list traversed in
> >> > > >non-reader section!!
> >> > > >>
> >> > > >> [ 330.303303] =============================
> >> > > >> [ 330.303307] WARNING: suspicious RCU usage
> >> > > >> [ 330.303311] 5.6.0-rc1+ #5 Not tainted
> >> > > >> [ 330.303315] -----------------------------
> >> > > >> [ 330.303319] drivers/base/power/main.c:1698 RCU-list traversed in
> >> > > >non-reader section!!
> >> > > >>
> >> > > >> [ 331.934969] =============================
> >> > > >> [ 331.934971] WARNING: suspicious RCU usage
> >> > > >> [ 331.934973] 5.6.0-rc1+ #5 Not tainted
> >> > > >> [ 331.934975] -----------------------------
> >> > > >> [ 331.934977] drivers/base/power/main.c:1238 RCU-list traversed in
> >> > > >non-reader section!!
> >> > > >>
> >> > > >> [ 332.467772] WARNING: suspicious RCU usage
> >> > > >> [ 332.467775] 5.6.0-rc1+ #5 Not tainted
> >> > > >> [ 332.467775] -----------------------------
> >> > > >> [ 332.467778] drivers/base/power/main.c:269 RCU-list traversed in
> >> > > >non-reader section!!
> >> > > >
> >> > > >I don't see these warnings in the kernels run locally here.
> >> > > >
> >> > > >What do you do to get them?
> >> > > >
> >> > > >Joel, any comments here?
> >> > >
> >> > > You have to enable lockdep in your config. Does your setup have that?
> >> >
> >> > CONFIG_LOCK_DEBUGGING_SUPPORT=y
> >> > CONFIG_PROVE_LOCKING=y
> >> > CONFIG_DEBUG_SPINLOCK=y
> >> > CONFIG_DEBUG_LOCK_ALLOC=y
> >> > CONFIG_LOCKDEP=y
> >>
> >>
> > I had CONFIG_PROVE_RCU_LIST = y and I think these warnings were triggered when I had closed my laptop (like just close without shutting down).
>
> OK, so let's define a macro for that in this file to avoid code duplication.
>
> And analogously in the second patch.
>
Sure, I will do it and send the patch soon.
> Thanks!